1. Field of the Invention
The present invention relates to an ignition system for an internal combustion engine, on which there exist increased requirements by (high pressure) supercharging and diluted mixtures, that are difficult to ignite (λ>>1, lean layer concept, high EGR rates).
2. Description of the Related Art
British patent document GB717676 shows a step-up transformer for an ignition system in which a circuit element, controlled by a vibration switch, of the type of a boost converter is used to supply a spark, generated via the step-up transformer, with electric power.
International patent application document WO 2009/106100 A1 shows a circuit configuration designed corresponding to a capacitor-discharge ignition system, in which energy stored in a capacitor is conducted, on the one side, onto the primary side of a transformer and, on the other side, via a bypass having a diode, to a spark gap.
US patent application publication document 2004/000878 A1 shows an ignition system in which an energy store on the secondary side, including several capacitors, is charged in order to supply a spark generated by a transformer with electric energy.
International patent application document WO9304279 A1 shows an ignition system having two energy sources. One energy source transforms electric energy via a transformer to a spark gap, while the second energy source is situated between a terminal on the secondary side of the transformer and the electrical ground.
As is known, ignition systems for internal combustion engines are based on a high-voltage generator such as a step-up transformer, using which, energy originating from the vehicle battery or a generator is transformed to high voltages, by which a spark gap is supplied, in order to ignite combustible mixture in the internal combustion engine. For this purpose, a current flowing through the step-up transformer is abruptly interrupted, whereupon the energy stored in the magnetic field of the step-up transformer discharges in the form of a spark.
In order to ensure the ignition of the combustion mixture particularly reliably, ignition systems are known in the related art which have a plurality of sparking events successively in time in order to increase the probability of the presence of an ignitable mixture at the location of one of the sparking events.
A further problem known from the related art is that the entire electric energy converted during the arcing has to be stored in the high-voltage generator, whereby the high-voltage generator becomes comparatively large and costly with that, and requires much installation space.
Based on the discharge characteristics of the high-voltage generator, such a high current flows at the beginning of the arcing that the electrodes of the spark gap are eroded. Therefore, such a high current is physically not required to guarantee a spark. Only the required duration of the arcing is ensured in this way, while one has to accept the disadvantages described above.
It is therefore one object of the present invention to remove the abovementioned disadvantages of the related art.